若a是锐角,且满足sin(a-π/6)=1/3,则cos a 的值为多少?

若a是锐角,且满足sin(a-π/6)=1/3,则cos a 的值为多少? 若A是锐角,且满足sin(A-(π/6））=1/3则cosA的值 若a是锐角,且满足sin(a-π/6)=1/3,则cos a 的值为多少?(希望能写出答题步骤) 若A是锐角,且满足sin(A-30)=1/3,则cosA的值为 若a是锐角,且sin(x-π/6)=1/3,则cosx等于? 若a是锐角且sin（a-π／6）=1／3则cosa的值为 若a为锐角,且sin(a-π/6)=1/6,求sina的值 已知A,B是锐角,A+B≠π/2,且满足3sinB=sin(2A+B)求证tanB≤2^(1/2)/4 若α是锐角,且满足sin（α-π/6）=1/3,求cosα的值 a是锐角,且sin（a－π／6）＝1／3,则cosa为 1-sin a+sin a的平方-sin a的立方+……若a是正锐角,且sin a-cos a=0.5,求1-sin a+sin^2a-sin^3a+…… 已知a.b为锐角,且满足3sin^2a+2sin^2b=0.求证a+2b=π/2 锐角A满足2sin(A-15)=根号三,则角A是? 锐角A满足sin（A-15度）=1/2 则角A的度数是 若a是锐角,且满足sin(a-π/6)=1/3,则sina 的值为多少?帮我看看哪里错了?1、sin(a-π/6)=1/3和cos（a-π/6）=2 √2/3拆开 求sina和cosa,但为什么求出sina=√3/2,cos=5/6,与题不符? a为锐角,且sin(a-π/6)=1/3,则cosa=? 若在锐角△ABC中,满足a^2+b^2=6abcosC,且sin^2(C)=2sinAsinB,则角C的之为 若x是锐角,且满足sin(x-pai/6)=1/3,则cosx等于多少